917 research outputs found
Preliminary technical and economic analysis of a hyperloop line: case study from Italy
The future of mobility and transportation infrastructures has been heavily questioned during the last years. Today we are looking at how the mobility of people and goods will evolve in the coming years. With reference to this topic, Hyperloop has been at the core of the debate. Scientists and engineers believe that this technology is a great opportunity for the modern society. Nonetheless, it still presents several unsolved issues. The purpose of this work is to propose a methodology to perform technical and economic pre- feasibility studies related to the hyperloop system, with specific focus on transport demand analysis, transport sizing of the infrastructure and cost analysis of CAPEX - CAPital EXpenditure and OPEX - OPerating EXpense. For the evaluation of the potential demand, the paper refers to the Multinomial Logit model, calibrated through SP â Stated Preferences surveys. Once the Logit model has been calibrated, it is possible to envisage different scenarios, such as maximum transport demand or maximum revenue, which will be used for the subsequent design of the transport system. As far as the sizing is concerned, some technical parameters of the project are required, such as: length of the route, maximum speed, and acceleration. The combination of the scenarios defined through the calibration of the Logit model and the project parameters, allows to define several scenarios representing the potential performances of the analyzed system. Given the possible performances of the transport service, an analysis of costs and potential revenues that determines the most efficient solution can be carried out. In addition, parametric values per km can be used to define CAPEX and OPEX. The methodology illustrated above, has been applied to a case study in Italy of the Rome-Milan OD (Origin â Destination), as it is one of the national routes with the highest volume of traffic and the largest number of modal choices
A synbio approach for selection of highly expressed gene variants in Gram-positive bacteria
Abstract Background The market for recombinant proteins is on the rise, and Gram-positive strains are widely exploited for this purpose. Bacillus subtilis is a profitable host for protein production thanks to its ability to secrete large amounts of proteins, and Lactococcus lactis is an attractive production organism with a long history in food fermentation. Results We have developed a synbio approach for increasing gene expression in two Gram-positive bacteria. First of all, the gene of interest was coupled to an antibiotic resistance gene to create a growth-based selection system. We then randomised the translation initiation region (TIR) preceding the gene of interest and selected clones that produced high protein titres, as judged by their ability to survive on high concentrations of antibiotic. Using this approach, we were able to significantly increase production of two industrially relevant proteins; sialidase in B. subtilis and tyrosine ammonia lyase in L. lactis. Conclusion Gram-positive bacteria are widely used to produce industrial enzymes. High titres are necessary to make the production economically feasible. The synbio approach presented here is a simple and inexpensive way to increase protein titres, which can be carried out in any laboratory within a few days. It could also be implemented as a tool for applications beyond TIR libraries, such as screening of synthetic, homologous or domain-shuffled genes
A comprehensive search for hot subdwarf stars using Gaia and TESS I. Pulsating hot subdwarf B stars
Hot subdwarf B (sdB) stars are evolved, subluminous, helium-burning stars,
most likely formed when red-giant stars lose their hydrogen envelope via
interactions with close companions. They play an important role in our
understanding of binary evolution, stellar atmospheres, and interiors. Within
the sdB population, only a small fraction are known to exhibit pulsations.
Pulsating sdBs have typically been discovered serendipitously in various
photometric surveys, lacking specific selection criteria for the sample.
Consequently, while individual properties of these stars are well-known, a
comprehensive understanding of the entire population and many related questions
remain unanswered. The introduction of Gaia has presented an exceptional chance
to create an unbiased sample by employing precise criteria and ensuring a high
degree of completeness. The progression of high-precision and high-duty cycle
photometric monitoring facilitated by space missions such as Kepler/K2 and the
Transiting Exoplanet Survey Satellite (TESS) has yielded an unparalleled wealth
of data for pulsating sdBs. In this work, we created a dataset of confirmed
pulsating sdB stars by combining information from various ground- and
space-based photometric surveys. Utilizing this dataset, we present a thorough
approach to search for pulsating sdB stars based on the current Gaia DR3
sample. Using TESS photometry, we discovered 61 new pulsating sdB stars and 20
variable sdBs whose source of variability remains to be determined through
future spectroscopic follow-up observations.Comment: 22 pages, 9 Figures - Accepted for publication in A&
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS : I. Asteroseismology of the GW Virstars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1â16
Context. The recent arrival of continuous photometric observations of unprecedented quality from space missions has strongly promoted the study of pulsating stars and caused great interest in the stellar astrophysics community. In the particular case of pulsating white dwarfs, the TESS mission is taking asteroseismology of these compact stars to a higher level, emulating or even surpassing the performance of its predecessor, the Kepler mission. Aims. We present a detailed asteroseismological analysis of six GW Vir stars that includes the observations collected by the TESS mission. Methods. We processed and analyzed TESS observations of RX J2117+3412 (TIC 117070953), HS 2324+3944 (TIC 352444061), NGC 6905 (TIC 402913811), NGC 1501 (TIC 084306468), NGC 2371 (TIC 446005482), and K 1â16 (TIC 233689607). We carried out a detailed asteroseismological analysis of these stars on the basis of PG 1159 evolutionary models that take into account the complete evolution of the progenitor stars. We constrained the stellar mass of these stars by comparing the observed period spacing with the average of the computed period spacings, and we employed the individual observed periods to search for a representative seismological model when possible. Results. In total, we extracted 58 periodicities from the TESS light curves of these GW Vir stars using a standard prewhitening procedure to derive the potential pulsation frequencies. All the oscillation frequencies that we found are associated with g-mode pulsations, with periods spanning from âŒ817 s to âŒ2682 s. We find constant period spacings for all but one star (K 1â16), which allowed us to infer their stellar masses and constrain the harmonic degree ` of the modes. Based on rotational frequency splittings, we derive the rotation period of RX J2117+3412, obtaining a value in agreement with previous determinations. We performed period-to-period fit analyses on five of the six analyzed stars. For four stars (RX J2117+3412, HS 2324+3944, NGC 1501, and NGC 2371), we were able to find an asteroseismological model with masses that agree with the stellar mass values inferred from the period spacings and are generally compatible with the spectroscopic masses. Obtaining seismological models allowed us to estimate the seismological distance and compare it with the precise astrometric distance measured with Gaia. Finally, we find that the period spectrum of K 1â16 exhibits dramatic changes in frequency and amplitude that together with the scarcity of modes prevented us from meaningful seismological modeling of this star. Conclusions. The high-quality data collected by the TESS space mission, considered simultaneously with ground-based observations, provide very valuable input to the asteroseismology of GW Vir stars, similar to the case of other classes of pulsating white dwarf stars. The TESS mission, in conjunction with future space missions and upcoming surveys, will make impressive progress in white dwarf asteroseismology
Pulsating hydrogen-deficient white dwarfs and pre-white dwarfs observed with TESS: I. Asteroseismology of the GW Vir stars RX J2117+3412, HS 2324+3944, NGC 6905, NGC 1501, NGC 2371, and K 1-16
In this paper, we present a detailed asteroseismological analysis of six GW
Vir stars including the observations collected by the TESS mission. We
processed and analyzed TESS observations of RX J2117+3412, HS 2324+3944, NGC
6905, NGC 1501, NGC 2371, and K 1-16. We carried out a detailed
asteroseismological analysis of these stars on the basis of PG 1159
evolutionary models that take into account the complete evolution of the
progenitor stars. In total, we extracted 58 periodicities from the TESS light
curves using a standard pre-whitening procedure to derive the potential
pulsation frequencies. All the oscillation frequencies that we found are
associated with g-mode pulsations with periods spanning from s to
s. We find constant period spacings for all but one star, which
allowed us to infer their stellar masses and constrain the harmonic degree
of the modes. We performed period-to-period fit analyses on five of the
six analyzed stars. For four stars, we were able to find an asteroseismological
model with masses in agreement with the stellar-mass values inferred from the
period spacings, and generally compatible with the spectroscopic masses. We
estimated the seismological distance and compared it with the precise
astrometric distance measured with GAIA. Finally, we find that the period
spectrum of K 1-16 exhibits dramatic changes in frequency and amplitude. The
high-quality data collected by the TESS space mission, considered
simultaneously with ground-based observations, are able to provide a very
valuable input to the asteroseismology of GW Vir stars, similar to the case of
other classes of pulsating white-dwarf stars. The TESS mission, in conjunction
with future space missions and upcoming surveys, will make impressive progress
in white-dwarf asteroseismology.Comment: 34 pages, 33 figures, 21 tables. Accepted for publication in
Astronomy and Astrophysic
The Effects of the Cultivar and Environment on the Phenolic Contents of Hazelnut Kernels
Different climatic conditions are known to affect the synthesis of primary and secondary metabolites. Therefore, the phenolic contents in new growing areas could affect the quality and flavor of hazelnuts. The aim of this study was to determine the variability of the phenolic contents of the kernels in different commercial hazelnut cultivars depending on their growing area. Five cultivars (âTonda Gentile delle Langheâ, âMerveille de Bollwillerâ, âPauetetâ, âTonda di Giffoniâ, and âBarcelonaâ (syn. âFertile de Coutardâ)) grown in different European collection orchards were included in the study. High-performance liquid chromatography coupled with mass spectrometry was used to identify and quantify the phenolic compounds. Thirteen phenols were identified in the hazelnut kernels, including 7 flavanols, 2 hydroxybenzoic acids, 3 flavonols, and one dihydrochalcone. Catechin and procyanidin dimers were the main phenolic compounds found in the hazelnut kernels. The highest contents of catechin and total flavanols were determined in cultivars cultivated in Spain and northern Italy, and the lowest in Slovenia and France. Flavanols were the major phenolic groups independent of the place of cultivation, as they accounted for more than 50% of all phenolic compounds identified. The flavanols were followed by hydroxybenzoic acids, flavonols, and dihydrochalcones. Higher contents of flavanols and flavonols were found in kernels from areas characterized by higher natural irradiation, which stimulates their accumulation. The contents of hydroxybenzoic acids correlated with altitude, which stimulated phenolic acid synthesis. A negative correlation was observed between the dihydrochalcone content and annual rainfall, probably due to hydric stress.info:eu-repo/semantics/publishedVersio
Quality of care indicators for head and neck cancers: The experience of the European Project RARECAREnet
Background: Monitoring and improving quality of cancer care has become pivotal today. This is especially relevant for head and neck cancers since the disease is complex, it needs multi therapy, patients tend to be older, they tend to have comorbidities and limited social support. However, information on quality of care for head and neck cancers is scarce. In the context of the project "Information Network on Rare Cancers" we aimed to identify indicators of quality of care specific for the head and neck cancers management and to measure the quality of care for head and neck cancers in different EU Member States. Methods: We defined indicators of quality of care for head and neck cancers based on a multidisciplinary and expert-based consensus process at a European level. To test the proposed indicators, we performed an observational population-based retrospective study in four countries (Ireland, Italy, Netherlands, and Slovenia) in the years 2009-2011. Results: The main quality indicators identified are: availability of formalized multidisciplinary team, participation in clinical and translational research; timeliness of care, high quality of surgery and radiotherapy, and of pathological reporting. For head and neck cancers, the quality of care did not reach the optimal standards in most of the countries analyzed. A high proportion of patients was diagnosed at an advanced disease stage, showed delays in starting treatment (especially for radiotherapy), and there was only a very limited use of multi therapy. Conclusions: According to the achieved consensus, indicators of quality of care for head and neck cancers have to cover the patient journey (i.e., diagnosis and treatment). Our results, showed suboptimal quality of care across countries and call for solutions for ensuring good quality of care for head and neck cancer patients in all EU countries. One possible option might be to refer head and neck cancer patients to specialized centers or to networks including specialized centers
About the existence of warm H-rich pulsating white dwarfs
Context. The possible existence of warm (Teff ⌠19 000 K) pulsating DA white dwarf (WD) stars, hotter than ZZ Ceti stars, was predicted in theoretical studies more than 30 yr ago. These studies reported the occurrence of g-mode pulsational instabilities due to the Îș mechanism acting in the partial ionization zone of He below the H envelope in models of DA WDs with very thin H envelopes (MH/Mâ âČ 10-10). However, to date, no pulsating warm DA WD has been discovered, despite the varied theoretical and observational evidence suggesting that a fraction of WDs should be formed with a range of very low H content. Aims: We re-examine the pulsational predictions for such WDs on the basis of new full evolutionary sequences. We analyze all the warm DAs observed by the TESS satellite up to Sector 9 in order to search for the possible pulsational signal. Methods: We computed WD evolutionary sequences of masses 0.58 and 0.80 Mâ with H content in the range -14.5 âČ log(MH/Mâ)âČ - 10, appropriate for the study of pulsational instability of warm DA WDs. Initial models were extracted from progenitors that were evolved through very late thermal pulses on the early cooling branch. We use LPCODE stellar code into which we have incorporated a new full-implicit treatment of time-dependent element diffusion to precisely model the H-He transition zone in evolving WD models with very low H content. The nonadiabatic pulsations of our warm DA WD models were computed in the effective temperature range of 30 000 - 10 000 K, focusing on â = 1 g modes with periods in the range 50 - 1500 s. Results: We find that traces of H surviving the very late thermal pulse float to the surface, eventually forming thin, growing pure H envelopes and rather extended H-He transition zones. We find that such extended transition zones inhibit the excitation of g modes due to partial ionization of He below the H envelope. Only in the cases where the H-He transition is assumed much more abrupt than predicted by diffusion do models exhibit pulsational instability. In this case, instabilities are found only in WD models with H envelopes in the range of -14.5 âČ log(MH/Mâ)âČ - 10 and at effective temperatures higher than those typical for ZZ Ceti stars, in agreement with previous studies. None of the 36 warm DAs observed so far by TESS satellite are found to pulsate. Conclusions: Our study suggests that the nondetection of pulsating warm DAs, if WDs with very thin H envelopes do exist, could be attributed to the presence of a smooth and extended H-He transition zone. This could be considered as indirect proof that element diffusion indeed operates in the interior of WDs.Fil: Althaus, Leandro Gabriel. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Corsico, Alejandro Hugo. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Uzundag, Murat. Universidad de ValparaĂso; ChileFil: VuckoviÄ, Maja. Universidad de ValparaĂso; ChileFil: Baran, Andrzej S.. Obserwatorium na Suhorze; PoloniaFil: Bell, Keaton J.. University of Whashington; Estados UnidosFil: Camisassa, MarĂa Eugenia. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Calcaferro, Leila Magdalena. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: de GerĂłnimo, Francisco CĂ©sar. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas; Argentina. Consejo Nacional de Investigaciones CientĂficas y TĂ©cnicas. Centro CientĂfico TecnolĂłgico Conicet - La Plata. Instituto de AstrofĂsica La Plata. Universidad Nacional de La Plata. Facultad de Ciencias AstronĂłmicas y GeofĂsicas. Instituto de AstrofĂsica La Plata; ArgentinaFil: Kepler, Souza Oliveira. Universidade Federal do Rio Grande do Sul; BrasilFil: Silvotti, Roberto. Osservatorio Astrofisico Di Torino; Itali
Coronary optical frequency domain imaging (OFDI) for in vivo evaluation of stent healing: comparison with light and electron microscopy
Aims Coronary late stent thrombosis, a rare but devastating complication, remains an important concern in particular with the increasing use of drug-eluting stents. Notably, pathological studies have indicated that the proportion of uncovered coronary stent struts represents the best morphometric predictor of late stent thrombosis. Intracoronary optical frequency domain imaging (OFDI), a novel second-generation optical coherence tomography (OCT)-derived imaging method, may allow rapid imaging for the detection of coronary stent strut coverage with a markedly higher precision when compared with intravascular ultrasound, due to a microscopic resolution (axial âŒ10-20 ”m), and at a substantially increased speed of image acquisition when compared with first-generation time-domain OCT. However, a histological validation of coronary OFDI for the evaluation of stent strut coverage in vivo is urgently needed. Hence, the present study was designed to evaluate the capacity of coronary OFDI by electron (SEM) and light microscopy (LM) analysis to detect and evaluate stent strut coverage in a porcine model. Methods and results Twenty stents were implanted into 10 pigs and coronary OFDI was performed after 1, 3, 10, 14, and 28 days. Neointimal thickness as detected by OFDI correlated closely with neointimal thickness as measured by LM (r = 0.90, P < 0.01). The comparison of stent strut coverage as detected by OFDI and SEM analysis revealed an excellent agreement (r = 0.96, P < 0.01). In particular, stents completely covered by OFDI analysis were also completely covered by SEM analysis. All incompletely covered stents by OFDI were also incompletely covered by SEM. Analyses of fibrin-covered stent struts suggested that these may rarely be detected as uncovered stent struts by OFDI. Importantly, optical density measurements revealed a significant difference between fibrin- and neointima-covered coronary stent struts [0.395 (0.35-0.43) vs. 0.53 (0.47-0.57); P < 0.001], suggesting that differences in optical density provide information on the type of stent strut coverage. The sensitivity and specificity for detection of fibrin vs. neointimal coverage was evaluated using receiver-operating characteristic analysis. Conclusion The present study demonstrates that OFDI is a highly promising tool for accurate evaluation of coronary stent strut coverage, as supported by a high agreement between OFDI and light and electron microscopic analysis. Furthermore, our data indicate that optical density measurements can provide additional information with respect to the type of stent strut coverage, i.e. fibrin vs. neointimal coverage. Therefore, coronary OFDI analysis will provide important information on the biocompatibility of coronary stent
Flavonoidi kao inhibitori Lck i Fyn kinaza
Phosphorylation of tyrosine residues constitutes a unique signaling pathway involved in regulation of most cellular processes responding to different extracellular stimuli. The enzymes that carry out this modification are tyrosine kinases. These enzymes enable the transfer of Îł-phosphate from ATP to the phenol âOH group of tyrosine on protein substrates. Development of specific and potent protein kinase inhibitors is important not only for treatment of diseases, but also as a tool to investigate the physiological roles of protein kinases. Flavonoids are biologically active polyphenol compounds naturally occurring in many plants. They are recognized as inhibitors of Fyn and Lck protein kinases, two representatives of the Src family of non receptor kinases involved in T-cell signaling transport. In the described experiments, the inhibitory activity of flavonoids on Fyn and Lck kinases was monitored by the ELISA method. Myricetin showed the highest inhibitory effect, and no ATP-competitive mechanism of inhibition was observed on Fyn tyrosine kinase. The affinity of human Fyn and Lck for two different substrates, polypeptide polymer Poly Glu:Tyr (4:1) and peptide M3-01, was also tested.Tirozinska fosforilacija predstavlja jedinstveni mehanizam prijenosa signala primljenoga iz okoline do staniÄ ne jezgre koja Äe odgovoriti na podraĆŸaj. Velika skupina enzima odgovorna za provo|enje ove modifikacije poznata je pod jedinstvenim nazivom tirozinske kinaze. One omoguÄuju prijenos -fosfata ATP-a na âOH skupinu tirozina supstrata. Lck i Fyn su dvije nereceptorske Src tirozinske kinaze, koje su vaĆŸne komponente regulacije aktivnosti T-limfocita. Rezultati ispitivanja flavonoida, bioloĆĄki aktivnih polifenolnih spojeva prirodno prisutnih u mnogim biljkama, upuÄuju na njihov inhibitorni uÄinak na proteinske kinaze Fyn i Lck. NajveÄu inhibiciju pokazao je miricetin, a pri ispitivanju mehanizma inhibicije Fyn kinaze nije ustanovljena kompeticija s ATP-om. Ispitivanje potencijalne inhibicijske aktivnosti flavonoidnih spojeva prema kinazama Fyn i Lck, provedeno je ELISA metodom. Pri tome je uspore|en afinitet ispitivanih enzima prema supstratima s razliÄitim brojem skupina podloĆŸnih fosforilaciji, odnosno prema polipeptidnome polimeru glutaminske kiseline i tirozina Poly Glu:Tyr (4:1) i M3-01 peptidu. Razvoj uÄinkovitih kinaznih inhibitora vaĆŸan je ne samo za prevenciju i lijeÄenje mnogih bolesti veÄ i za bolje razumijevanje uloge proteinskih kinaza u organizmu
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